Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Tuesday, February 17, at 7:30 a.m. Cooke City Motorsports in partnership with the Friends of the Avalanche Center sponsor today’s advisory. This advisory does not apply to operating ski areas.
Under clearing skies mountain temperatures are a chilly 5F to 10F. Winds are currently blowing 10-20 mph out of the west to northwest except in Cooke City where they are much stronger and gusting to 35 mph. Today will warm into the upper 30s with moderate winds. High pressure will block any chance of precipitation and sunny spring-like weather is forecasted tomorrow. The big question is, do I keep my snow shovel on my porch or my skateboard?
Bridger Range Northern Madison Range Northern Gallatin Range
Weather stations measured 3-5 inches of snow yesterday morning, but Eric found closer to eight on Mt. Blackmore. He snapped a photo of trees hung heavy with fresh powder, a sight for sore eyes. I toured north out of Bridger Bowl to the Ramp with calm winds and a few inches of fresh snow (photo). We both went into the field to find out how the new snow bonded to the old snow surface and came up with the same answer: it bonded well. Eric only saw a few small, loose snow avalanches in steep terrain (photo). His snowpit (video) and mine (video) found very good stability. The only caveat is if the winds increase today the danger on wind-loaded slopes will also increase.
On Sunday a skier on Hyalite Peak backed off a slope he intended to ski when his snowpit showed instability (ECTP 6 and 17) on a layer of facets buried 10 and 40 cm deep. This is not widespread, but a small, one foot deep, skier triggered avalanche on Lone Peak last Thursday is further evidence of its existence. This is why we advocate digging pits; it’s the only sure-fire way to know what’s under our feet. For today, there are generally safe avalanche conditions and the danger is rated LOW, but as this skier reported, even during a low danger there are still isolated areas of unstable snow.
Southern Madison Range Southern Gallatin Range
Lionhead Area near West Yellowstone
The southern mountains (except Cooke City) have a layer of surface hoar buried one to two feet deep. These feathery crystals show up as a stripe in the pit wall if you shovel down a few feet. We have been finding this in most areas (Taylor Fork, Teepee Basin, Lionhead) but not on every slope. Mark made a video of this layer breaking clean in his stability tests on Lionhead. For today, the avalanche danger is rated MODERATE on slopes steeper than 35 degrees and LOW elsewhere.
Cooke City
Around Cooke City the main problem is wind-loaded slopes. Yesterday morning the area had 3-5 inches of new snow. Last night the winds started blowing strong, loading slopes and increasing the avalanche danger. The good news is that these areas are easy to find and avoid as wind plumes identify which slopes are getting drifted. For today, the avalanche danger is rated MODERATE on wind-loaded slopes and LOW elsewhere.
I will issue the next advisory tomorrow morning at 7:30 a.m. If you have any snowpack or avalanche observations drop us a line at mtavalanche@gmail.com or call us at 587-6984.
AVALANCHE EDUCATION and EVENTS
Take a look at our Education Calendar for all classes being offered.
TONIGHT: Snow Science and the Human Factor, Bozeman, MSU Procrastinator Theater, 6-8:00 p.m., Tuesday, February 17. The free event will feature a talk by Powder editor and MSU graduate John Stifter, multimedia presentations on the human factor in avalanche risk, a panel of experts from MSU’s Snow & Avalanche Lab and Gallatin National Forest Avalanche Center, as well as a Q & A session (poster).
Companion Rescue Clinic, Bozeman, REI, 6-8 p.m., Friday, February 20 and 10 a.m.-2 p.m. on Saturday, February 21 (field location TBD). Pre-registration is required: www.rei.com/stores/bozeman.html
1-hour Avalanche Awareness, West Yellowstone, Holiday Inn, 7 p.m., Saturday, February 21.
Companion Rescue Course for Snowmobilers, Cottonwood Drainage, Crazy Mountains, Saturday, February 21, 9:30 a.m. – 2 p.m. Please RSVP to your club officers or to kathrynjbarker@fs.fed.us if you are interested in participating.